Method and apparatus for continuous production of bags from thermoplastic film
US4867735A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 1, 1987 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Oct 1, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T156/1313
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method and apparatus are provided for continuous fabrication of bags from a longitudinally advanced multi-layer thermoplastic film web fed tangentially onto a rotating drum for carrying out transverse web seam welding and severing, the principal novel feature being provision of preliminary heating carried out across at least part of the width of web at which the final seam and sever is to take place. The preliminary heating step is advantageous where the thickness of film layers to be sealed and severed is not uniform across the width of the web or in which the uniform thickness of the film layers is such that seaming and severing in a single step requires an undesirably long time for continuous high speed production. The method can be adapted for production of bags of different widths.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.